Detection rules › Splunk
Suspicious Parent Process for lsass.exe or services.exe (Windows Event Log)
This use case detects when either the Windows local security authority subsystem (lsass.exe) or service control manager (services.exe) are executed as a child from an unexpected parent process. This can indicate process injection/hollowing, masquerading, or other suspicious activity. The expected parent process for these services is wininit.exe.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Privilege Escalation | |
| Stealth |
References
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Security-Auditing | Event ID 4688: A new process has been created. |
Rule body
id: '16171.24332'
title: Suspicious Parent Process for lsass.exe or services.exe
description: This use case detects when either the Windows local security authority
subsystem (lsass.exe) or service control manager (services.exe) are executed as
a child from an unexpected parent process. This can indicate process injection/hollowing,
masquerading, or other suspicious activity. The expected parent process for these
services is wininit.exe.
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR
"<EventID>4688<" OR Type=Process) ("lsass.exe" OR "services.exe") | regex process_path="(?i)\x5csystem32\x5c(lsass|services)\.exe"|
regex parent_process_name!="(?i)wininit\.exe"| where isnotnull(parent_process_name)
and not match(parent_process_name, "^-$") | table _time, host, user process, process_*,
parent_process_name, parent_process_* | bin span=1s | stats values(*) as * by _time,
host '
techniques:
- defense-evasion:masquerading:masquerade task or service
- defense-evasion:process injection
technique_id:
- T1036.004
- T1055
data_category:
- Windows event logs
references:
- https://andreafortuna.org/2017/06/15/standard-windows-processes-a-brief-reference/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR "<EventID>4688<" OR Type=Process) ("lsass.exe" OR "services.exe")
Stage 2: regex
| regex process_path="(?i)\x5csystem32\x5c(lsass|services)\.exe"
Stage 3: regex
| regex parent_process_name!="(?i)wininit\.exe"
Stage 4: where
| where isnotnull(parent_process_name) and not match(parent_process_name, "^-$")
Stage 5: table
| table _time, host, user process, process_*, parent_process_name, parent_process_*
Stage 6: bucket
| bin span=1s
Stage 7: stats
| stats values(*) as * by _time, host
Exclusions
The rule actively suppresses these predicates.
| Field | Kind | Excluded values | Search |
|---|---|---|---|
parent_process_name | regex_match | "(?i)wininit.exe" | excludes:parent_process_name |
parent_process_name | regex_match | "^-$" | excludes:parent_process_name |
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
EventCode | eq |
| field:"EventID" kind:eq value:"4688" |
parent_process_name | is_not_null | field:"parent_process_name" kind:is_not_null | |
process_path | regex_match |
| field:"process_name" kind:regex_match |
Search terms
These SPL tokens match against raw event text.
| Stage | Term |
|---|---|
| 1 | "<EventID>4688<" |
| 1 | "lsass.exe" |
| 1 | "services.exe" |